New insight into knockout reactions from the two-proton halo nucleus ¹⁷Ne

The unexplained disagreement in the dependence of spectroscopic factors (𝐶2⁢𝑆_exp) on the binding energy obtained by nucleon knockout using different targets is still a puzzle that needs to be addressed. To find an explanation of this riddle through exclusive measurements using different targets. The exclusive measurements were performed by using a ¹⁷Ne beam with an energy of 500 MeV/u incident on C and CH₂ targets. Through the standard theoretical approach, 𝐶^2⁢𝑆_exp were derived from the analysis of the experimental data on proton ejection from the proton halo in ¹⁷Ne as well as from its core ¹⁵O. For the C target, proton ejection from the proton halo gave 𝐶²⁢𝑆_exp about 37% smaller than for the H target. But when protons are ejected from the core of ¹⁷Ne, 𝐶²⁢𝑆_exp are identical within statistical uncertainties. An explanation for the difference in 𝐶²⁢𝑆_exp could be the removal of both halo protons, a more important reaction pathway for the C target. The 𝐶²⁢𝑆_exp values obtained by analyzing the proton ejection from the core indicate that it is not affected by the interaction with the halo protons.. Authors: Wamers, F. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt (Germany); et al.]; Lehr, C. [Technische Universität]; Marganiec-Gałązka, J. [Technische Universität; Radioisotope Centre POLATOM (POLATOM)]; Aksouh, F. [GSI Helmholtzzentrum für Schwerionenforschung GmbH; King Saud University]; Aksyutina, Yu. [GSI Helmholtzzentrum für Schwerionenforschung GmbH]. DOE Contract: FG02-08ER41533. Subjects: 6 ≤ A ≤ 19; Knockout reactions; Nuclear reactions; Nucleon distribution; Physics